Ledford’s execution marks the first for the state of Georgia for 2017.

He had been on death row for a quarter-century after murdering his 73-year old neighbour, Harry Johnston, in 1992.

Ledford's lawyers had asked for his client to be put to death by firing squad -- an unusual request which was rejected on Monday by a court which considered it a delaying tactic.

The State Board of Pardons and Paroles in Georgia also rejected an appeal for leniency requested by Ledford.

The execution comes less than a month after four inmates were put to death in one week in Arkansas, as the southern US state rushed to schedule the deaths before the expiration of a drug used in lethal injections.

That state had planned to put eight convicted murderers to death in 11 days -- a record, had it been carried out -- but four won reprieves.